Safety stop for bed and cylinder printing presses



J. F. BANTHIN Jan. 27, 1953 SAFETY STOP FOR BED AND CYLINDER PRINTING PRESSES J. F. BANTHIN 2,626,564

SAFETY STOP FOR BED ANDl CYLINDER PRINTING PRESSES Jan. 27, 1953 5 Sheets-Sheet 2 Filed NOV. 16, 1949 INVENTOR.

ATTORNEY J F. BANTHIN Jan. 27, 1953 SAFETY STOP FOR BED AND CYLINDER PRINTING PRESSES Filed Nov. 16, 1949 5 Sheets-Sheet 3 l Illl Il INVENTOR. nHNl-T B ANTI-.UN

AETTORNEY SAFETY STOP FOR BED AND CYLINDER PRINTING PRESSES Filed Nov. 16, 1949 J. F. BANTHIN Jan. 27, 1953 5 Sheets-Sheet 4 4 0 9 l 3 87 0 00 E 9 2 I m 8 9 W9 I Z w a ,E 2 u n l 76 \7 -3 W 9 n l WMM@ E PW. W7/1. .1| l 8 Ju M, bl EHU/a #L www?. www FHawJ mw -/56 J. F. BANTHIN Jan. 27, 1953 SAFETY STOP FOR BED AND CYLINDER PRINTING PRESSES Filed NOV. 16, 1949 5 Sheets-Sheet 5 JNVENTOR. JUHN'BANTHIN BY E Z ATTORNEY Patented Jan. 27, 1953 OFFICE SAFETY STOP FOR BED AND CYLINDER PRINTING PRESSES John F. Banthin, Bridgeport, Conn.

Application November 16, 1949, Serial No. 127,706

'Ihis invention relates to new and useful improvements in printing presses of the type including an impression cylinder having on and off positions and transfer means including a suction system for moving a sheet from a stack to such impression cylinder together with other transfer means for moving a printed sheet from said cylinder and has particular relation to automatic stop-means for such a press.

An object of the invention is to provide in a printing press of the character outlined means for automatically and substantially instantly bringing the printing press to a complete stop on accidental loss of suction in said suction system such as may occur on failure of said transfer means to receive a sheet from said stack or on failure of such transfer means to properly hold a sheet received from the stack and on failure of. the transfer means to receive a sheet from said impression cylinder, respectively.

Another object is to provide in a printing press including an impression cylinder, transfer means for moving a sheet from a stack to said cylinder and other transfer means for moving a sheet from said cylinder, means tov stop said printing press on failure of said other transfer means to receive a sheet from said impression cylinder.

A further object is to provide in a printing press including an impression cylinder and a transfer means including a suction system and sucker feet for moving a sheet from a stack to said impression cylinder and a second transfer means including delivery grippers for moving a sheet from said cylinder, means for automatically and substantially instantly bringing the press to a stop on accidental failure of the suction pressure in said suction'system and on failure of said delivery grippers to receive a sheet from said cylinder.

Yet another object is to provide in a printing press including an impression cylinder and means including delivery grippers for receiving sheets from said cylinder'and moving them from the vicinity thereof, means for preventing damage to said press and spoilage of work by the packing of sheets about said impression cylinder due to failure of said delivery grippers to remove sheets from the vicinity of the impression cylinder.

Another object is to provide in a printing press including an impression cylinder and means including delivery gripers for receiving a sheet from said cylinder and moving the sheet from the vicinity of said cylinder, of means for automatically and substantially instantly stopping said printing press on failure of the delivery grippers 5 Claims'. (Cl. 101-278). y

to receive a sheet from said impression cylinder.

Ar still. further object is to provide in a printing press including an impression cylinder and transverse means including delivery grippers for moving a sheet from said impression cylinder of means including electromagnetic means for au-y tomatically and substantially instantly stopping said printing press on failure of said gripper iingers to receive a sheet from said cylinder, at least one of said grippers including means operable under such circumstances to close a circuit to said electro-magnetic means.

Other objects and advantages of the invention will become apparent from a consideration of the following detailedv description taken in ,connec-Y tion with the accompanying drawings wherein a satisfactory embodiment of the invention is shown. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall Within the spirit of the invention andthe scope of the appended claims.

ln the drawings:

Fig. 1 is a side elevational view showi ng a portion of a printing press having the present in-` vention incorporated therein.

Fig. 2 is a side elevational view of a portion of the press shown in Fig. l, but on a larger scale;v

Fig. 3 is a further enlarged view partly in side elevation and partly in section and showing tripping mechanisms of the invention;

FFigs. 4 is a top plan viewof the mechanisms of Fig; 5 is an exploded view in perspective and substantially on the scale of Figs. 3 and 4 and showing the relationship of parts when the stop mechanism of the invention has been tripped;l

Fig. 6 is a top plan view showing certain portions of Fig. 2 but on a larger scale;

Fig. '7 is a view looking as from the left in Fig. 6; and

Fig. 8 is an enlarged view partly in side elevation and partly in section and showing a delivery gripper of the invention.

Referring in detail to the drawings, at Ill is generally indicated a printing press and the same comprises a base or frame Il which may be in the form of a single casting, generally rectangular in plan. Mounted on the frame II, as by bracket or bearing means I2, is an impression cylinder I 3. Operable below such impression cylinder in the usual manner is a type bed I4 adapted to be reciprocated in certain timed relation with vertical movements ofl the cylinder I3, as is customary in the art.

At I5 is shown a support for a stack of sheets IB of paper or other material to be printed and sheet transfer mechanism, generally designated |1, is designed for removing the sheets one at a time from the stack I5 and delivering such sheets, as removed, to the impression cylinder I3. This transfer mechanism I1 includes a pivoted arm I3 pivotally mounted as at I9 and designed to be rocked about said pivot in a path to have the transfer mechanism deliver a sheet from the stack I6 to the impression cylinder |3 and to then have a return movement to pick up the next sheet from the stack, etc.

For the operation of the transfer mechanism I1 I have shown a crank arm 20 as an extension of the arm I8 and a link 2| pivoted at its respective ends to said crank arm and a rocker 22 for rocking the transfer mechanism through the above described path of movement. Rocker 22 is pivoted intermediate its ends as at 23 and mounts a roller 24 located in a groove 25 in a cam 26 secured to a shaft 21 also having secured thereto a gear 28 meshing with a driving gear 29 on a shaft 30. This mechanism is more fully described in my application for Patent Serial No. 745,262, filed May 1, 1947.

Actually there are two of the arms I8 employed and between their upper ends they mount a man1- fold 3| from which flexible tubes or the like 32 connectA with the vacuum suckers 33 commonly employed in the art. From a suitable source in a suction system, a suction or vacuum is applied to the manifold 3| and thence through the tubes 32 to the vacuum suckers 33. This suction is applied in certain timed relation with operations of the press, all as is usual in the art, and customarily the suction is on the suckers when they are over the stack, as in Fig. 1, whereby they pick up the top sheet from the stack.

Then, in the normal operation of this type of press, the transfer or feeding mechanism is swung forwardly about the pivots |9 until the suckers approach head stops 34 when the vacuum system is open to atmosphere whereby the vacuum suckers release the sheet against the head stops whereupon the forward edges of the sheets are engaged by the grippers (not shown) of the impression cylinder. Thereafter, return movement is applied to the transfer mechanism I1 and the vacuum suckers 33 are carried back to their loading or pick-up positions over the stack IS.

Suction to the vacuum suckers 33 originates in a vacuum pump 35 driven by a motor 36 through pulleys 31 and a belt 38. From the vacuum pump 35, a pipe 39 connects with a T-tting 40, one branch of which mounts a vacuum gage 4| while a tube or pipe 42 from its other branch leads to a control valve device 43 which at predetermined times is maintained open to atmosphere by a latch 44 to break the suction in the system, as fully describedin my co-pending application Ser. No. 29,012, filed May 25, 1948. From such control valve device, a tubing 45 connects with one end of the manifold 3| for the application of a suction thereto.

At times the vacuum suckers 33 may pick up a sheet of paper in a disarranged or inclined position whereby its forward edge is not straight across, or the suckers may drop the sheet part way to the head stops 33, or the like. Under such circumstances, the improperly placed sheet will probably get out of position in the press and later, particularly if there are several such sheets, they will become jammed about the impression cylinder and other adjacent parts and likely result in bending or breaking or distortion of some parts.

It will be understood in this connection that prior to my invention, as disclosed in my application Ser. No. 29,013, iiled May 25, 1948, if the vacuum suckers drop the sheet too soon, or in improper alignment, the operation of the press will continue and the suckers 33 of the transfer mechanism |1 will continue to shift sheets from the stack toward the impression cylinder. According to the invention of my last identified application for patent, means are provided whereby on the untimely opening of the vacuum system to atmospheric pressure, the press will be stopped almost instantly. Thus, in a press equipped with that mechanism, should one of the vacuum suckers 33 be exposed, as it will be if a sheet is held at an angle or in improper alignment, the opening of the vacuum system to atmosphere through even one vacuum sucker will cause such a drop in the vacuum pressure that the mechanism of that application will go into operation and bring about substantially instant stopping of the press.

Under such circumstances, the operator or attendant will, of course, know that something is wrong and he can then remove the improperly placed or disarranged sheet and reset the mechanism and again start the press into operation. Thus, an accumulation of sheets in positions about the impression cylinder or adjacent parts will be prevented and in this connection it will be understood that when the press is stopped by the mentioned mechanism and then again started it will continue the uninterrupted cycle so that its cycle of operation will be that for which the press was originally set.

The present invention makes use of the mechanism of my application Ser. No. 29,013 above reierred to and such mechanism is herein included in combination with other safety features, all looking to a more perfect control or" a printing press and to the prevention of casual damage to such a press. Thus, to the desired end, on the near side of the press frame II there is mounted a control box 43, the power leads to which may run through a conduit 41 and from Such control box a conduit 48 carries leads to a micro switch 49 also mounted on such side of the press frame. Operation of this micro switch by means to be described results in opening of a main switch or circuit breaker or the like within the control box 45 whereby the power to the press is cut off. The operating button of the micro switch 49 is desighated 50 and is shown as projected toward the delivery end of the press. This particular location is a matter of convenience.

The main drive shaft of the press |0 is designated 5| and on said shaft is a ywheel 52 and a drum 53. Shaft 5| and thus the flywheel 52 and drum 53 are driven by a belt 54 from any suitable source of power and through a belt 55 passing about a small pulley 56 fast on the shaft 5| other parts of the press may be driven. Since the drive from the shaft 5| to the various parts o f the press is old and well known and conventional structure it is not deemed necessary to confuse or enlarged the present disclosure by disclosing such drive.

About the drum 53 a brake band 51 is located and the same is provided with any frictional material 58 designed to be drawn against said drum for the purpose of braking the press. One end of this band 51 is suitably anchored as at 59 to a side Wall 60 of the frame while the other end of; theibandis anchored' as; at 6|; to: an arm; 6.2' of a1 lever generally.l designated 5.3. Intermediate its ends; this lever ispivotaly mounted at 64 and then. the; second.` army 6.5.- of the lever is carried upwardly and at its upper end is provided withv a laterally extendinglug 59, the purpose of. which will appear. Also at. its upper. end. thei lever.r is provided with a. projection or' extensionY 9.1 constituting a hand piece for use in rocking the lever.

AI coil' spring 68.- anchored at one end to the f-rameawall. 6|] as.y atv 69 has its otherend anchored to a; stud 1:9 rigid with the lever arm 65- toward thef upper end of the: latter. Clearly, the spring [i8v is'V constantly tending to. rock thev lever 63 about the-pivot 64 ina counterclockwise direction and. in ay direction to. tighten the brakeband 5.1 aboutv the drum 53 to draw the friction pador 5.9. of. suchY brake band. into. tight engagementwith. the4 drum whereby to provide abrakz.- ing action for. the. whole. press'.v

livotallyl mounted. on the framewall 99, as by astudV 1|, is a trigger device generally designated 1.2; and. in. side. elevation generally of inverted. T formation. Thus, the trigger-12 comprises a generallyl vertical arm 13 comprising the stemof the T anda pair of oppositely extending generally horizontal arms 1liv and 15 together comprising the head of the T. A short stud or shaft 19 onl the trigger arm 15 mounts: a roller 11A designed to engage and press' inwardly on the operating stem or buttonv 59 of the microswitch |19 whereby to trip said switch, as will appear.

Trigger arm 14 is laterally thickened andl enlarged on its inner side toward its free end and is provided with a notch 18 designed to substantially receive or to receive a substantial part of theenlargement, projection or protuberance: 69 at the upper end ofthe lever arm 65 when the trigger 12v is functioning to retain the lever 63 in a-.brakel release position against the tendency of the spring 68 to move said. lever to a brake applied position.

Extending outwardly from the near side of the stemz13 of the trigger 12 is a short projection. or stud 19 comprising a finger or hand piece for convenient use in manually rocking said trigger for the resetting of the present mechanism, as will presently appear. In its inner side, at its upper end, the trigger arm or stem 13 is laterally enlarged providing a shoulder or surface 99 designed to be engaged by a projection or pin 8| of a trip` mechanism generally designated 82 at predetermined times, as will be set forth.

The` trip mechanism 82. is moreV particularly shown, cris better shown, inFigs. 3 and 4 of the drawings. There it will beI seen that such mechanism includes. a bracket' 83` secured to the side 6a of the press i9 as; by bolts 84 passing through openings 85 in a thickened or pad-like portion 86 of said bracket. In addition to said pad-like portion, the bracket includes a forwardly extending elongated arm 81 and an upstanding rigid lug-like portion 33 at right angles to the arm 81 and located approximately atv the juncture of said arm and the pad-like portion 89 of the bracket.

Toward its forward, end the bracket arm 81 mounts a stud 89 projecting from the inner side of said arm and passing through a lever 99 intermediate the ends of the latter but in eccentric relation to the mid point thereof. Thus', in the drawings, the stud 89 is located forwardly of the midportion of the lever 9|) whereby said lever is overbalanced toward its rear end and its rear portion or its portion to the right of the pivot 8.95 (Figs. 3. ande). dverbalances the. leverportion to. the, l'cft.v of. saidpivot. Therefore,` the lever under.- the iniiuence. of` gravity constantlyr tends to moveto: and. below the full line; position of Fig; Sin a clockwise', direction or in a. direction to; carry its forward or shorter end portion upwardly.

Extending laterally.- from the inner side of the forward end. portion of the lever 9|? are a pair of studs 9| and 92 passing through slots 93v and 99'; respectively, inthe elongated body portion 9.51' of a dog 95 which -at its forward endv is provided with an upstanding tooth 91 straight at its inner side. whereby to provide a shoulder or contact part 98. The pin 8! above referred to is shown as extending entirely through the body v 95 of the dog 99. and includes a portion 99- projecting at the inner side of such body. Anchored aty one end to this pin portion 99 a relatively heavy coil spring I 901 which at its other endV is anchored to a stud lill projecting from the inner side of the level' 99.

With this construction, spring |99 is constantly tending to close and therefore is constantly drawing inwardly on the dog 99 in a manner to bring the body portion 95 of said dog into overlapping relation with the forward end portion of lever 99. Thus, the spring |99 tends constantly to maintain the dog 96 and the lever 9a in such relation that the studs 9| and 92' are always in the forward end portions ofthe slots 93 and 94, respectively. From the foregoing it will be seen that the lever 99 constitutes a primary member of the tripY mechanism and the dog 99 constitutes a secondary member.

As will later appear, the trip mechanism 82 particularly the dog 96 thereof, cooperate with a pawl or dog actuating part |92 mounted at the near Side and toward the forward edge of the bed I4, as 0n a stud or the like |03. The mounting and purpose of the pawl |92 will later be fully set forth but here it is noted that the pawl is` located laterally of one edge of the type bed le and that such pawl includes an arm |04 and Ia headv |95, the latter including a straight or fiat forward surface |96 and a bevelled or inclined lower surface |91. It will be understood that during use of the press, and in each cycle of the press operation, the type bed I5 is moved through a. complete reciprocation. That is, it is moved rst in one direction and then in the opposite direction under the cylinder i3.

Asv they type bed moves toward the feeder end of the press (that. end of the press supporting the stack. of sheets i9.) the bevelled or. inclined surface |91 of the. pawl |92 may. rideV over the bevelled surface of the: tooth 91 should the latter be. in the path of movement of the pawl and then under certain predetermined conditions, as will. be described, when the bed moves in the oppositev direction as the dog 99 is in the position shown. in full lines in Fig. 31 its shoulder 98 will be engaged by the straight or fiat surface |99 of the pawl 592 and the dog will be drawn forwardly a predetermined distance with the type bed M to bring about. movement of the trigger 12 and release of the lever 93, all as will be more particularly set forth.

A wing-like arm |98 is secured as by bolts |99 to the lug or upstanding extension 88 of the bracket 83 and such wing serves to support a body lill.. This body H9 is provided with -a cylindrical chamber opening through its lower end and through a. lateral orice ||2 communieating with a passageway H3, in turn communieating with a port or lateral opening I |4 in which is threaded one end of a tube or pipe IIS. Such tube or pipe I|5 is, through a piece of exible tubing or the like IIS, in communication with the manifold 3|. Extending through the lower open end of the chamber III is a cylindrical plunger I |1 at its lower end provided with a bifurcated head I I8 shown as straddling the longer end portion of the lever 3|) and secured thereto by a cross pin IIS passing through the lever and the arms of the bifurcated head IIS. This pin I I9 is rigid with the head I I 8 but passes through an elongated opening |20 in the lever Si) for a certain relative movement of these parts, as will be clear. In addition to the head I I8, the plunger II1 includes a cylindrical portion |2I slidable in the chamber I II and open at its inner end.

An adjusting screw |22 enters the chamber III through the upper end of the body I I0 and within such chamber engages a sleeve |23, which sleeve is of a diameter to telescopically enter the inner or open upper end of the cylindrical portion |2| of plunger II1. This latter plunger may be described -as spring loaded since a coil spring |24 is located within such plunger and the inner end portion of sleeve |23 and at one end bears against `a part of said sleeve and at its other end against the head |13 of the plunger. Clearly, this coil spring tends to project the plunger from the chamber I I and to resist slight movement of the plunger into said chamber.

At its upper end, screw |22 is provided with a knurled head |25 for use in adjusting the screw and a lock nut |26 is provided for securing the screw in adjusted positions and against casual movement relative to the body IIS. This screw is adapted for adjustment to move the sleeve |23 longitudinally of the chamber II to vary the pressure or" the spring |24 on the plunger head |I8. The bracket arm 31 is provided with an opening |21 and the longer arm portion of lever 90 is provided with an opening |28. It will be clear that through the tube III:l the vacuum or suction system connected with the vacuum suckers 33 is also connected with the chamber III and when vacuum is applied to this system and the same is closed to atmosphere the suction resulting in the chamber draws the plunger ||1 inwardly of such chamber rocking the lever B Ato the dot and dash line position of Fig. 3. In this position of the parts, the hole |28 aligns with the hole I 21.

When setting up the press and timing it, the lever St may be manu-ally rocked to this dot and dash line position and then a cotter pin or the like, as shown at |23 in Fig. Ll, is passed through the aligned holes to maintain the lever 95 and the dog 95 in the dot and dash line operating position while the press is being timed and is manually operated through its normal cycle. When the press is in use, the cotter pin or other means |29 is removed from the openings |21 and |28 and the latter have no function. That is, this cotter pin |29 and these holes |21 and |28 are only used in set-ups or for adjustments of the press to prevent the present stop means from acting while the press is being manually moved through its cycle and testings for necessary adjustments or for other set-up purposes.

In the operation of the press III, the transfer mechanism I1, vacuum 'being present in the described system when in the position of Fig. l, through its vacuum suckers 33 takes the .top-

most sheet from the stack I5. At this time, the

impression cylinder I3 is in its upper or off 8 position. Through conventional press mechanism, the transfer means is shifted and delivers this sheet to the head stops 34 to be engaged by the gripper buttons (not shown) of the impression cylinder I3.

At the time of the delivery of a sheet to the impression cylinder, the vacuum system is open to atmosphere as by means disclosed in my application Ser. No. 745,262, breaking the suction on the Vacuum suckers 33 whereby to have the latter release the sheet. As the transfer mechanism returns toward the stack I6 the cylinder I3 is lowered to on position and the bed I4 carries the type under the cylinder and into engagement with the sheet on the latter whereby such sheet is printed. This is conventional. At this time, the vacuum system is closed to atmosphere and so there is a suction through the manifold 3| and the tube IIB and tube ||5 to the chamber and the plunger I1 is in its inner or upper position and the lever is in the dot and dash line position of that ligure. Thus, as the bed I4 moves, the surface |01 of the pawl I 02 will not strike the dog but will merely pass above the same.

Now, on failure of vacuum in the vacuum system as, for example, if one of the vacuum suckers 33 is exposed to the atmosphere because a sheet is not properly held or is not sealing such vacuum sucker, the vacuum fails or at least falls in the chamber |I| and the plunger II1 moves downwardly allowing the lever 9B to drop or pivot to its full line position of Fig. 3. As this occurs, the lever 98 carries the dog 96 to the full line position of the latter in said figure. Now, as the bed I4 continues movement toward the left in Fig. 3, the surface |06 of the pawl |02 will engage the shoulder :'38 of the tooth 91 of dog 96 in a manner to move or drag said dog toward the left with such movement of the type bed. Such movement of dog is possible against the resistance of the spring |00 and results in some elongation of said spring. However, as the dog is so moved, it moves relative to the lever 9|) since the latter is mounted on the stud or pivot 89 and is not capable of longitudinal movement.

The slots 93 and 94 receiving the studs 9| and 92 permit of longitudinal movement of the dog 96 relative to the lever 9B. However, it is noted that the slots 93 and 94 incline upwardly toward one another so that their inner or adjacent end portions are higher than their outer or remote end portions. Thus, as the dog 36 is moved by the pawl |32, the dog not only moves outwardly or toward the left in Fig. 3 but its front or toothed end portion 91 also must move downwardly. The pins and slots cause a cam-like action.

As the dog so starts to move, the pin -or projection 8| of the dog is bearing against the shoulder or surface 8|) of the stem 13 of the lever or trigger 12. Thus, this lever or trigger must rock in a counterclockwise direction. As it so rocks its roller 11 swings upwardly and depresses the microswitcli actuator 5d opening the power circuit of the press by the tripping of a switch or circuit breaker or the like in the control box 36. This cuts off the power to the press.

Additionally, vthe described movement of the trigger 12 carries the shoulder or notch 18 of the outer end portion of its arm 14 downwardly releasing the lug or lateral extension EB at the upper end of the arm 65 of lever 63. Immediately such .lug 56 is released the spring 63 rocks the lever 53 1n a counterclockwise direction about the pivot 64 tightening the brake band 51 and drawing its frlctional lining 58 tight against the drum 53 whereby `a .braking .action'is applied to the power shaft At 4this time, it will be understood that power has been cut off by interruption of the circuit in the primary motor and the application of the brake as described results in the whole press being rapidly brought to a standstill.

When the dog 96 'reaches the dot and dash line position'of Fig. 3 it will be clear that the pawl ||i2 may then pass over the dog so that there will be no damage to any part. Further, it will be clear that the pin of the dog need only cause overbalancing of the trigger 'l2 to carry the notch '18 of thelatter downwardly sunicient to release the extension |56 of the lever 63. Immediately this is done, the brake is applied and immediately prior to such operation the vroller ll has actuated the control element 50 of the microswitch. rlhus, if the vacuum suckers 33 are not all sealed 'by a sheet being transferred, or .if they are carrying no sheet, the press is stopped so .that investigation may be made as to the improper operation of the press before any damage is caused.

Thus, according Vto the present construction herein disclosed, the transfer mechanism cannot be delivering sheets at an angle or in the wrong way to the impression cylinder so as to clog Aup thepress or .cause other trouble. Unless the transfer means is operating properly, the vacuum Iin the vacuum system fails and the plunger I-I'I drops resulting in movement of the dog 96 to the full line position of Fig. 3 where such dog will be engaged .by the pawl |62 and the trip device 82 is moved to open the power circuit to the press and to admit of applicationof the braking mechanism.

After the operator has remedied any defects and removed any misplaced sheets or vthe like, he draws the lever B3 to brake release position by using the handle Y61 and actuates the trigger l2 back to set position with its recess 'i8 receiving the lug or y.extension 66 of the lever 63 and wi-th the surface 8B of said lever adjacent the pin 8|. In this connection, it will be understood that immediately the press is tripped the dog 9S has been moved to the ybroken line position of Fig. 3 and the straightedge |06 of the pawl |02 passed over the tooth 91 of `the dog so the latter has been freed yand by the spring |90 is immediately returned to its normal Iposition awaiting the resetting of trigger 12 and the lever 63.

Thedescribed means operates to stop the printing press without destroying the established cycle of operation of the latter. Therefore, when a dimculty has been remedied the operator merely resets the trigger 63 and the press starts up at any place in its established cycle at which place it was stopped. Further, the press mechanism is effective to automatically stop operation of 'the press after the last sheet has .been fed or transferred from the stack I6 to the impression cylinder I3. At such time when the vacuum suckers 33 .are Areturned to the feeder table, there .is no sheet for them to pick upor to seal them `and thus the vacuum system remains open to atmospheric pressure through the vacuum suckers 33 and the present mechanism is set into operation and the entire press brought to a standstill.

The pawl |02 in .the present disclosure is replacing .the plate 1.9 of my application Ser. No. 29,013 and in the present disclosure has a functionin addition .to its function already described herein. This separate function is to operate the above described trip mechanism on the failure of delivery 'grippers to receive -or to :remove a sheet from the impression cylinder I3. It will .be 111iderstood that should the transfer mechanism I] continue to deliver sheets to the Aimpression cylinder and should the proper portions ofthe press fail to remove such sheets from the impression cylinder, .a number of the sheets will become wedged vand press about and under the cylinder resulting .in damage to the Press and costly work spoilage. Thus, I have provided means forsetting the .above described tripping mechanism into operation to open the power circuit of the press and to apply the brake on failure of transfer means, including delivery grippers for removing sheets from the impression cylinder, to receive during any cycle of the machinesoperation, .a sheet from such cylinder.

This second transfer means I have gener-' ally designated |39 and the same vincludes a frame structure including an upright |3| shown on `the inner sideofthe machine I0 and a similar upright (not shown) opposite upright or braclneit |3I.. These .uprights or brackets are fastened .to

and movable with the type bed I4 and between their upper ends support bar |32 (see Fgs- 6 and '7) along which .at the desired spaced intervals `are mounted the desired number of delivery grippers, of which Vbut two are shown, 'being `generally designated |33 and |34, respectively. The delivery gripper |34 may be of the exact construction .as that disclosed in my applicationSer. No. 729,492, led February 19, 1947 `v(now VPatent No. 2,509,030 of May `23, 1950), .while the-delivery gripper |33 has been slightly modified.

This delivery gripper is shown alone in Fig, A8 and therein comprises a frame generally designated |35 and which is .blanked and formed from sheet metal as, for example, steel. |35 is elongated and is transversely U-shaped. Thus, the frame comprises ,a pair `of side walls `|36 and |37 and a'bottom wall |38. In theirforward portions the side Walls are relatively shallow and` together with the forward Aportion Vof the bottom wall define a channel |39 in which are .mounted a gripper shoe |`f| and a gripper finger IM.

Bottom wall '|38 has the major portion of ther gripper shoe thereagainst and such shoe is secured in place as Yby rivets Ilil? passing through an inner portion of the shoe and said bottom wall.

The forward end portion |3 of the shoe extendsy forwardly of ythe frame |35 and is .curved slightly upwardly as shown. In their forward Yend portions, the side walls |3 and |37 are .bent inwardly las at |64 and then outwardly providing wing-like' portions |45, asis customary in the art.

lThe gripper finger MI Vis located above the shoe and is p'ivotally mounted Vas on a short shaft or bar IE6 supported in the frame side walls l|36 and |37. Pivot pin or bar |45 Vis of ,steel vand 1s chrome plated 'for long wear. Aspring |41 includes .a pair of eye portions Aist located about the .shaft |136, one at each side of the nger IM,

and further includes arms U19 and a blight .pon-v tion 50, the latter being .disposed under the inner end of the gripper finger llii. Inadditiomspring the proper pressure on the inner end portion 'ofv the gripper linger |4| will overcome thgspring' The frame' |41 and result in the nger being rocked to carry its forward end upwardly away from the shoe.

' Rearwardly of the gripper nger |4| the side walls |36 and |31 of the frame |35 are widened or heightened providing relatively deep sides or portions |53. A slot |54 is provided in the side wall portions and enters from the rear end-s thereof and extends to a point spaced a slight distance rearwardly from the rear end of the gripper nger |4|. Extending continuously about said slot |54 is an angularly related flange |55, which ange serves to very materially strengthen the frame structure at this point. Slot |54 is of reduced width in its inner end portion and preferably terminates in an arcuate end |56 for engagement with a portion of the surface of a cam shaft or gripper finger operating means |51.

In its larger rear portion, the slot |54 is designed to receive the supporting bar |32 and preferably at this portion the slot is carried inwardly or restricted as at |58 so that such restricted portions are engaging the outer forward portion of the bar |32 when the frame |35 is mounted on the latter and cam shaft |51. The continuous ange |55 bears against the bar |32 and the shaft |51 whereby the latter are not engaged merely by the edges of the side wall portions of the frame but are engaged over a substantial area. It is noted that the supporting bar |32 and the cam shaft or gripper nger operating means |51 are in substantially parallel relation.

A rivet or other means |59 is used to mount or secure a double nut |66 against the underside of the rearward portion of the bottom wall |38 of the frame |35. Substantially aligned with the nut |60 but straddling the upper edges of the rearward portions of the side walls of the frame is a lock cap |6|. This cap comprises an upper wall portion |62 extending over the upper edges of the side walls of frame |35 and further includes side portions |63 disposed at the outer sides of the upper edges of said side walls. In addition, lock cap |6| includes end flanges |64 located between the side wall portions of the frame at the respective ends of the'top wall portion |62 of said lock Cap.

When a delivery gripper is to be mounted on the supporting bar |32 and the cam shaft |51, the gripper is simply moved in the direction of its length after aligning its slot |54 with such bar and shaft whereby to dispose the latter in the illustrated positions of Fig. 8 within said slot. Thereafter, bolts |65 are passed downwardly through the wall |62 of the lock cap and at each side or preferably in engagement with the bar |32. These bolts are then threaded into tapped holes provided in the double nut |60. If desired, spring lock washers |66 are placed under the heads of said bolts.

The supporting bar |32 being mounted by the upper ends of the brackets |3| and the latter being mounted by the type bed I4, it will be clear that said supporting bar as well as the various delivery grippers mounted thereon and the cam shaft |51 will move with the type bed and thus will be carried forwardly toward the impression cylinder |3 and rearwardly therefrom. Additionally, the cam shaft |51 is adapted for rocking or oscillating movement, as is old in the art.

The cam shaft is operated in timed relation with other operations of the press, as is the practise in the art, to rock the gripper nger |4| to the position of Fig. 8 against the tendency of the spring |41 and to release the gripper finger for movement by said spring whereby to have the forward end portion of the gripper nger move to or toward gripping relation with the upper surface of the inclined portion |43 of the gripper shoe |46. To the desired end, a collar |61 is mounted on the cam shaft |51 and is located between the side walls of the frame |35. This collar carries a radially projected pin |68.

As the bar |32 and shaft |51 are moved forwardly carrying the delivery grippers, carn shaft |51 is oscillated to rock its collars |161 and the pins |63 are carried downwardly against the Arear portions |65 of the gripper fingers |4| rocking the latter on their pivots |46 to the position of Fig. 8. Thus, after the proper forward movement, a sheet of paper or other material is received from the impression cylinder between the open ends of the shoe |48 and the fingers |4|, as between the end |43 of the shoe and the surface |52 of the finger.v

Then the cam shaft is rocked in the opposite direction carrying the pin |68 away from the inner or rear end of the finger |4| whereupon the spring |41 acts to rock the finger back towards a gripping relation with the shoe. Thereafter the shaft |52 starts rearwardly, the received sheet is shifted rearwardly, and at or toward the end of the stroke the cam shaft is again rocked or oscillated t0 have the pins |68 of the various grippers rock the ngers |4| of the latter against the tendency of the springs |41 so as to have the fingers release the sheet. At such time, as is customary in the art, the released sheet is received on belts or conveyors |18 supported as by bracket |1| and located immediately below the path of movements of the grippers,

The particular gripper |33, as above mentioned, is of slightly modified construction. Preferably, this gripper is the middle gripper of those mounted on the supporting bar |32. The modification consists in a slight change or addition in the gripper linger |4 For the present purpose, an opening is formed through the forward end portion of said finger and'in such opening there is located a tubular insulator |12 through which extends a lead |13, the conductor |14 of which is electrically connected with a button-like contact or head |15 located at the lower side 0f the lower bevelled surface portion |52 of the gripper finger.

Lead |13 (see especially Fig. 6) is carried rearwardly with respect to the gripper nger |33 and through a hole |16 is carried into the supporting bar |32 and extends entirely through the same to the inner end thereof and where it emerges from the shaft or bar it is identified as |11. The lead is secured against an upright or bracket |3| by a clamp |18 and is electrically connected with a magnet or solenoid |19 mounted against the outer side of said bracket. From such solenoid or magnet |19 a lead |88 extends to a spring pressed ball contact |8| suitably mounted on a part of the type bed |4 as in a block of Micarta or other insulating material |82. t will be clear that the ball contact |8| together with the magnet or solenoid |13 and the other electrical parts thus far described all move as a unit with the delivery grippers and the type bed.

Bolts |83 (Figs. 6 and 1) extending from the inner side of the frame wall 66 mount a platelike support |84, the same being held in spaced relation to the Wall 68 as by collars 0r spacers |85 located about the bolts |83. This support or plate |84 is of electrically insulating material. On the upper edge of the support |84 is a conductor |86 in the form of an L-shaped strap. Such conductor has one arm extending across the upper edge of the support |84 and the other arm ancestor;v

against theside of said support and is: clamped'in place as by a strap |81. A bolt or binding post |88 anchors the upper end of a lead |89 electrically with the conductor |86 While its lower end is connected with a transformer |90 clamped onto brackets |91 supported on the inner side of the wall 60. A second lead |92 from the transformer |90 is grounded on one of the brackets IBI as at |33 (Fig. 6). The supply line to the transformer is illustrated at |94.

It Will be understood that the transformer being grounded to one of the brackets |9I, the latter being secured to the wall 60 of the machine frame or base, that the transformer is grounded. Further, it will be apparent that the gripper shoe |40 of the delivery gripper |33 is grounded as through the frame of the gripper and the supporting bar |32 and brackets |3| and the type bed, etc. to the frame of the press.

Except when the delivery grippers are in their forward positions to receive a sheet from the impression cylinder I3, the ball contact |8| is spaced rearwardly from the elongated track-like contact |83. This is clear from Fig. 6. However, when the delivery grippers are moved forwardly or are in their forward positions, such as positions in which they are to receive a printed sheet from the impression cylinder I3, the ball contact |8| is onthe elongated track-like contact |36. At this time, the circuit from one side of the transformer is grounded on the frame of the press and from the other side of the transformer the circuit is through lead |39 to contact |86 through ball contact |8| to lead |00 through the solenoid or electro magnet |19 and lead |11 plus lead |13 to the contact button |15on the underside of the finger |41. The transformer |90 is a step-down transformer and the voltage from the transformer is very low as, for example, about 12 volts.

Thus, the circuit at the time indicated being as above described, the only thing needed to close the circuit is for the contact button |15 to engage the upper side of the inclined portion |43 of the gripper shoe |30. As has been indicated, but a very low voltage is being used and when the cam shaft |51 is reversed to release the gripper finger IM of delivery gripper |33, the spring |41 rocks such'finger into gripping position and a piece of paper or the like is clamped between the forward portion of the gripper nger and the portion |3 of the gripper shoe. The di-electric properties of even a sheet of paper are sufcient to insulate the gripper finger and the gripper shoe and no circuit is closed through the solenoid or electro magnet |19. Under such circumstances, the operation of the machine continues through its normal cycle.

However, if the delivery gripper |33 fails to receive a sheet of paper or the like from the impression cylinder, contact button |15 directly engages the upper surface of the inclined portion |43of the gripper shoe |40 and a circuit is closed through the solenoid or electro magnet |10. When this occurs, the pawl |532 is rocked from the position of Figs. 1 and 2 to the position of Fig. 3. The result of such movement will later be set forth in detail but now it is though best to consider the manner in which the closing of the circuit brings about this movement of the pawl. Thus, a core |95V is moved'upwardly when the solenoid or electromagnet |19v is energized. This core at its lower end is rigidly secured to a pin |93 `extending inwardly through a slot |91 inthe tail. end portion. |04 ofthepawr |02.

and slot connection between the core 19.5 and the' pawl |02 is necessary since the core has a. straight vertical movement and the pawl must rock about the pivot |03.

When the magnet or solenoid is energized, pawl |02 is rocked in a counterclockwise direction about the pivot |03 and such movement is limited by a stop pin |58. Then when the magnet or solenoid is de-energized (this being its normal condition during normal cycle of the machines operation), core |95- drops downwardly and the pawl |02 rocks in a clockwise direction on the pivot |03 and such movement of the pawl is limited by a stop pin |99. This movementy to normal position of the pawl is solely under the influence of gravity since the core plus the tail portion of the pawl is of suiiicient mass to overbalance the head portion of the pawl as the latter is mounted on the stud or pivot |03.

During the normal cycle of the machines operation, transfer means |1 delivers a sheet to be printed to the impression cylinder and retreats to take another sheet from the stack IE- and a printing cycle is performed and the printed sheet is taken from the impression cylinder by the delivery grippers and carried rearwardly and delivered onto the belts |10 which carry the` printed sheet away. A preferably transparent piece 200 disposed over the roller 25| keeps the newly printed sheet from Contact with the latter or any adjacent parts. In this connection, it will be understood that the grippers are gripping one edge portion of the sheet, i. e., its lead edge portion, and that otherwisev the sheet is not supported by the grippers and that its trailing edge would drag onto the roller 20| or onto adjacent parts except for the presence of protecting sheet 200. f

After the grippers deliver a sheet onto the belts |10 they are returned toward the impression cylinder to receive the second sheet therefrom. rIhus, the two transfer means l1 andY |30 operate in timed relation with operation of the impression cylinder and the type bed, etc. As long as the two transfer means are operating properly, the present stop means does not function and is merely stand by.

On failure of the transfer `means I1 to; receive a sheet from the stack I6, or ifr a sheet is not properly received as, for example, if it isr at an angle or the like so that one ofthe vacuum suckers 33' is not sealed by the sheet, the suction pressure fails in the vacuum system and the plunger |1 drops permitting the lever to move about' the pivot 89 from the dotr and dash line to the full line position of Fig. 3. This carries thedog 96 upwardly as to thev full line position of Fig. 3` and eventhough the pawl |02 is in its normal' position (solenoid or magnetY |13 not being energized) the lower portion of the forward surface |05 of the pawl will engage the surface 98 of the dog andV drag the same forwardly tripping or releasing the trigger 12 and bringing about opening ofY the power circuit of the press and the application ofthe brake bandV 51 to the drum 53 to bring the press to a stop;

Of course, at this time, pawl |02 stays in its normal position since now all the power to the pressv is cut olf. In this normal position of the pawl, as long as the dog 93 is held in its normal position for operation of the press, the pawl will not engage the latter. Further details of the stopping of the press on failure of vacuum in the 5 suction system has previously been given`- and itz is believed that angle of the disclosure has been suciently covered.

As has been previously suggested, if the transfer means |1 is continuously delivering paper or other material to be printed upon to the impression cylinder and such material is not being carried from the impression cylinder by the trans.- fer means |03, the material will pack about the impression cylinder and it has happened that this material is so tightly packed and compressed that adjacent portions of the machine have been broken. Such feed of sheets to the impression cylinder and failure of removal of the sheets from such cylinder also results in spoilage of work, perhaps in a run of expensive stock. This may occur where the operator moves from one machine to another or otherwise leaves an operating machine being satised that there is an ample supply of sheets in the stack I6. The means by which the machine is stopped on failure of the transfer means |30 to remove a sheet from the Vicinity of the impression cylinder will now be described.

Should the grippers be in their forward positions, a low voltage circuit is closed with the eX- ception of the slight gap between the contact button |15 at the underside of gripper finger |4| and the upper side of the angular or bent portion |43 of the gripper shoe |40. Now, if the gripper fails to receive a sheet from the impression cylinder and the cam shaft |51 operates in its usual cycle so that the gripper finger |5| is released to the action of the spring |41, the contact button is moved against the gripper shoe |40 closing the above mentioned low voltage circuit.

That circuit includes the solenoid or magnet |19 and the latter being energized the pawl |02 is rocked to the position of Fig. 3. In this position of the pawl the lower portion of its flat forward face |06 will engage the surface 98 of the tooth 91 of dog 96 even though such dog is in its normal position being held there by the lever 90 which is in its normal position, wherein it is supported by the plunger |1 due to the presence of suction in the vacuum system of the transfer means |1.

As the pawl engages the tooth 91 in the manner described, the dog 96 is drawn forwardly against the tendency of the spring |00 and the projectingend portion of the pin 8| riding against the surface portion 80 of trigger 12 rocks the same in a counterclockwise direction causing its roller i1 to depress the actuator 50 of the micro switch i9 to bring about opening of the power circuit of the press. Further, the slight movement of the trigger 12 in the direction indicated carries its shoulder or surface 18 from in front of the eX- tension 85 of lever 63 whereby the latter is released to movement under the iniiuence of the spring 69 and the brake applied to the drum 53 as previously set forth. This brings the entire press to a stop.

The operator then understands the reason why the grippers have not received a sheet from the impression cylinder, makes any corrections or adjustments necessary and then moves the brake lever 63 to release the brake and resets the trigger 12 to hold the brake in off position and the cycle of the machines operation may be continued on reclosing of the necessary switch. In this connection, it will be understood that when the power to the press was cut off, the low voltage to the magnet or solenoid |19 was cut oif so that the pawl |02 has returned to its normal position, as in Figs. 1 and 2.

Having' thusV set'forth the nature of my invention, what I claim is:

1. In a printing press including an impression cylinder, a first transfer mechanism for transferring sheets from a pile to said cylinder, said transfer mechanism including a suction system, a second transfer mechanism for transferring sheets from said cylinder,V said second transfer mechanism including a delivery gripper and means for moving the same toward said cylinder to receive a sheet and to then move the delivery gripper from the cylinder to carry the received sheet from the vicinity of the cylinder, an electric power circuit, a switch controlling said power circuit, means for applying a braking action to a given part of the press, a trigger having a normal position maintaining said braking mechanism inoperative, means mounting said trigger for movement from said normal position to a released position to release said braking mechanism, said switch positioned to be engaged and operated by said trigger as the latter moves from its normal to its released position, a trip mechanism including a mounting bracket secured on the press, a substantially horizontal lever pivoted intermediate its ends to said bracket, a substantially vertical body on said bracket and having a cylindrical recess opening through its lower end, a plunger including a portion in said recess and a head at the lower end thereof and connected with one end portion of said lever, a pair of studs extending substantially horizontally from one side of the other end portion of said lever, a dog comprising an elongated body portion against said side of said end portion of said lever and extending beyond the outer end of said end portion of the lever and having an upstanding tooth on its portion beyond said end portion of the lever, said dog having a pair of slots through said body portion and through which said studs extend, a spring anchored at one end to said dog and at its other end to said lever and normally urging said dog toward a retracted side-by-side relation with said end portion of said lever whereby the dog is located with the studs in the forward ends of the respective slots, said slots inclining from their outer toward their inner or adjacent ends whereby said dog is normally held by said spring in a position with its toothed portion extending upwardly at an incline and whereby on said dog being moved forwardly to a projected position relative to said lever said studs will be in the relative portions of said slots and said dog body will be substantially parallel with said lever, said cylindrical recess connected in the vacuum system of said iirst transfer mechanism whereby when said system is lled said plunger is drawn into said recess, said plunger when drawn into and held in said recess holding said lever in a position with said dog substantially horizontal, a part movable with a movable part of the press and adapted to engage and shift said dog to projected position against the tendency of said spring, said dog adapted when shifted to projected position to engage and move said trigger from its normal to its released position to open said switch and release said braking mechanism for braking action on said given part of the press, said plunger while in said cylindrical recess and'under'the control of the suction of the suction system ofthe first mentioned transfer mechanism supporting said lever in a position maintaining said dog out of the path of movement of said Dart movable with a mov- .-of suction 17 in said suction system toV be released to'A permit of rocking movement of said Vlever whereby to-carry said dog into a position to be engaged by Vsaid part movable with a moving part of the press, said part movably mounted on said moving part of the press and normally positioned to pass by said dog when the latter is in its first mentioned position, and means under thecontrol of said delivery gripper of the second transfer mechanism for moving said part into position to engage said dog when the latter is in its first mentioned position on failure of the delivery gripper to receive a sheet from said impression cylinder.

2. In a printing press including an impression cylinder, a transfer mechanism for transferring sheets from a pile to said cylinder, a second trans- .fer mechanism for transferring sheets vfrom said cylinder, a frame, a-bed reciprocable on -said frame beneath said cylinder, power means, control means operable to control said power .means whereby the press is started and stopped, 'trigger means for effecting the operation of said control means, and a trigger tripping mechanism comprising a primary member movably mounted on said frame for movement from a normal .position to a moved position, means under the control of one of said transfer mechanisms yfor moving said primary member intov its moved position on failure of said transfer mechanism to transfer a sheet, a secondary member movably .mounted on said primary member for moi/ement from a normal position to a moved position in which .latter position it actuates said trigger means in control operating direction, an actuating part for said secondary member movably mounted on said ,reciprocating bed for movement from a normal position to a moved position, a contact part on said secondary member arranged to be contacted by said normally positioned actuating part as it reciprocates in the direction of the trigger actuating direction of movement of said secondary member, said contact part being out of the path of said normally positioned actuating part in the normal position of said primary member and being moved into said path in the moved position of said primary member, and means under the control of the other of said transfer mechanisms for moving said actuating part, on failure of said other of said transfer mechanisms to transfer a sheet, into position to engage said contact part when said primary member is in its normal position. l

3. In a printing press including an impression cylinder, a transfer mechanism for transferring sheets from a pile to said cylinder, said transfer mechanism including a suction system, a second transfer mechanism for transferring sheets from said cylinder, said second transfer mechanism including a delivery gripper and means for moving the same toward said cylinder to receive a sheet and from said cylinder to carry the received sheet therefrom, a frame, a bed reciprocable on said frame beneath said cylinder, power means, control means operable to control said power means whereby the press is started and stopped, trigger means for effecting the operation of said control means, and a trigger tripping mechanism comprising a primary member movably mounted on said frame for movement from a normal position to a moved position, vacuum operated means under the control of said suction system of said first transfer mechanism for moving said primary member into its moved position on failure of suction in said suction system, a secondary 18Ay member movably mountedon said primary member for movement from a normal position to a moved position in which latter position it actuates said trigger means in control operating direction, an actuating part for said secondary member movably mounted on said reciprocating bed for movement from a normal. position to a moved position, an electromagnet operable upon being energized to move said actuating part from its normal to its moved position, a circuit for said electromagnet, a contact part on said secondary member arranged to be contacted by .said normally positioned actuating part as it `reciprocates in the direction of the trigger actuatingdirection of movement of said secondary member, said contact part being out of the path of said normally positioned actuating part in the normal position of said primary member and being moved into said path in the moved position of said primary member, and means whereby on failure of said delivery gripper of said second transfer mechanism to receive a sheet from said impression cylinder said circuit is closed to energize said electromagnet to move said actuating partl into position to engage said contact part when vsaid primary member is in its normal position.

4. In a printing vpress including an impression cylinder, a transfer mechanism for transferring sheets from a pile to said cylinder, said transfer mechanism including a suction system, a second transfer mechanism for transferring sheets from said cylinder, said second transfer mechanism including a delivery gripper and means for moving the same toward said cylinder to receive a sheet and from said cylinder to carry the received sheet therefrom, a frame, a bed reciprocable on said frame beneath said cylinder, power means, control means operable to control said power means whereby the press is started and stopped, trigger means for effecting the operation of said control means, and a trigger trip-ping mechanism comprising a lever pivotally mounted on said frame intermediate the ends of said lever, a vacuum operated plunger in communication with said suction system connected with one arm of said lever and adapted to draw said arm in one direction while vacuum is applied to said plunger whereby the other arm is moved in the opposite direction, lever actuating spring means arranged to move said lever in the opposite direction upon failure of the vacuum, a dog, means mounting said dog on said other arm of said lever for swinging movement therewith and for longitudinal movement thereon from a normal position, spring means exerting longitudinal force in one direction on said dog to return it to normal position from a longitudinally moved position,` trigger actuating means on said dog arranged to move said trigger means in control operating direction through longitudinal movement of said dog in opposition to said last mentioned spring means, a dog actuating pawl movably mounted on said reciprocating bed for movement from a normal position to a moved position, a pawl engaging part on said dog arranged to be contacted by said normally positioned pawl as it reciprocates in the direction of the trigger actuating direction of longitudinal movement of said dog, said pawl engaging part being out of the path of said normally positioned pawl in the vacuum moved position of said lever and being moved into said path by said lever actuating spring means upon failure of said vacuum, and means under the control of said delivery gripper of the second transfer mechanism for moving said pawl into :rematar 'position to engage said pawl engaging part of said dog, when said lever is in its vacuum moved position, on failure of the delivery gripper to Areceive a sheet from said impression cylinder.

5. In a printing press including an impression cylinder, a transfer mechanism for transferring sheets from a pile to said cylinder, said transfer mechanism including a. suction system, a second transfer mechanism for transferring sheets from said cylinder, said second transfer mechanism including a delivery gripper and means for moving the same toward said cylinder to receive a sheet and from said cylinder to carry the received sheet therefrom, a frame, a bed reciprocable on said frame beneath said cylinder, pov-Jer means, control means operable to` control said power means whereby the press is started and stopped, trigger means for effecting the operation of said control means, and a trigger tripping mechanism comprising a lever pivotally mounted on said frame intermediate the ends of said lever, a vacuum operated plunger in communication with said suction system connected with one arm of said lever and adapted to draw said arm in one direction while vacuum is applied to said plunger whereby the other arm is' moved in the opposite direction, lever actuating spring means arranged to move said lever in the opposite direction upon failure of the vacuum, a dog, means mounting said dog on said other arm of said lever for swinging movement therewith and for longitudinal movement thereon from a normal position, spring means exerting longitudinal force in one direction on said dog to return it to normal position from a longitudinally moved position, trigger actuating means on said dog arranged to move said trigger means in control operating direction through longitudinal movement of said dog in opposition to said last mentioned spring means, a dog actuating pawl i 20 movably mounted on said reciprocating bed for movement from a normal position to a moved position, an electromagnet operable upon being energized to move said pawl from its normal to its moved position, a circuit for said electromagnet, a pawl engaging part on said dog arranged to be contacted by said normally positioned pawl asV it reciprocates in the direction of the trigger actuating direction of longitudinal movement of said dog, said pawl engaging part on said dog being out of the path of said normally positioned pawl in the vacuum moved position of said lever and being moved into said path by said lever actuating spring means upon failure of said vacuum, and means whereby on failure of said delivery gripper to receive a sheet from said impression cylinder said circuit is closed to energize said electromagnet to move said pawl into position to engage said pawl engaging part of said dog when said lever is in its vacuum moved position.

JOI-IN F, BANTHIN,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,351,175 Lehr Aug. 31, 1920 1,691,656 Kelly Nov. 13, 1928 1,741,848 Kelly Dec. 31, 1929 1,779,310 Fischer Oct. 21, 1930 1,790,465 Dudley Jan. 27, 1931 1,886,281 Low Nov. 1, 1932 2,320,100 Rupp May 25, 1943 2,356,058 Hunting Aug. 15, 1944 2,392,391 Kaddeland Jan. 8, 1946 2,392,392 Kaddeland J an. 8, 1946 2,509,030 Banthin May 23, 1950 

